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Founder  Joined: 18 Apr 2015
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DBC + BCD or 90 [#permalink]
Expert's post 00:00

Question Stats: 86% (00:49) correct 13% (00:01) wrong based on 15 sessions
Attachment: triangle.jpg [ 9.24 KiB | Viewed 496 times ]

$$AD=BD=6$$, $$\angle ADB = 90°$$

 Quantity A Quantity B $$\angle DBC+ \angle BCD$$ $$90°$$

A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.

Kudos for R.A.E
[Reveal] Spoiler: OA

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Last edited by chetan2u on 28 Nov 2018, 06:28, edited 2 times in total.
edited the question Director Joined: 20 Apr 2016
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WE: Engineering (Energy and Utilities)
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Re: DBC + BCD or 90 [#permalink]
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Carcass wrote:
Attachment:
triangle.jpg

$$AB=BD=6$$, $$\angle ABD = 90°$$

 Quantity A Quantity B $$\angle DBC+ \angle BCD$$ $$90°$$

A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.
Kudos for R.A.E

Since $$\angle ADB = 90°$$, therefore$$\angle BDC = 90°$$

Now in $$\triangle DBC$$, we have

$$\angle BDC = 90°$$

and as the sum of angles in a $$\triangle$$add up to 180°

therefore

$$\angle DBC+ \angle BCD = 90°$$

Hence option C
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Re: DBC + BCD or 90 [#permalink]
Expert's post
Carcass wrote:
Attachment:
triangle.jpg

$$AB=BD=6$$, $$\angle ABD = 90°$$

 Quantity A Quantity B $$\angle DBC+ \angle BCD$$ $$90°$$

A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.

Kudos for R.A.E

Ofcourse there is a typo as $$\angle ABD = 90°$$ should be $$\angle ADB = 90°$$

now by the property of an exterior angle in a triangle, it is equal to the sum of opposite angles, so
$$\angle ADB = 90°=\angle DBC+ \angle BCD$$=A=90=B

C

Actually irrespective of AD=BD or not the answer will be C.

A poor question with wrong equivalence etc
Pl relook into the source.
_________________

Some useful Theory.
1. Arithmetic and Geometric progressions : https://greprepclub.com/forum/progressions-arithmetic-geometric-and-harmonic-11574.html#p27048
2. Effect of Arithmetic Operations on fraction : https://greprepclub.com/forum/effects-of-arithmetic-operations-on-fractions-11573.html?sid=d570445335a783891cd4d48a17db9825
3. Remainders : https://greprepclub.com/forum/remainders-what-you-should-know-11524.html
4. Number properties : https://greprepclub.com/forum/number-property-all-you-require-11518.html
5. Absolute Modulus and Inequalities : https://greprepclub.com/forum/absolute-modulus-a-better-understanding-11281.html Intern Joined: 21 Nov 2018
Posts: 21
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Re: DBC + BCD or 90 [#permalink]
1
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KUDOS
Please refrain from posting incorrect or misleading questions. You really shake the basic concepts of newbies like us .
AB can never be equal to BD. The question is wrong.
Founder  Joined: 18 Apr 2015
Posts: 6643
Followers: 107

Kudos [?]: 1274 , given: 6003

Re: DBC + BCD or 90 [#permalink]
Expert's post
To be honest this is a question that while ago I found on the section for the GRE of a University website if I remember well.

it is not proper a question that I have found on an obscure website.

it is true that is my fault to check every question I posted on the board but is not the end of the world to shake the knowledge base of a student that aims to achieve the top score.

The question is not good and moves on... That's it.

We have almost countless question already to exploit. Kindly regards
_________________ Re: DBC + BCD or 90   [#permalink] 28 Nov 2018, 07:16
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